Re: [PATCH v7 8/8] dmaengine: idxd: fix cdev setup and free device lifetime issues
From: Dan Williams <hidden>
Date: 2021-03-22 23:39:44
On Mon, Mar 22, 2021 at 4:32 PM Dave Jiang [off-list ref] wrote:
The char device setup and cleanup has device lifetime issues regarding when
parts are initialized and cleaned up. The initialization of struct device is
done incorrectly. device_initialize() needs to be called on the 'struct
device' and then additional changes can be added. The ->release() function
needs to be setup via device_type before dev_set_name() to allow proper
cleanup. The change re-parents the cdev under the wq->conf_dev to get
natural reference inheritance. No known dependency on the old device path exists.
Reported-by: Jason Gunthorpe <jgg@nvidia.com>
Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <redacted>[..]
quoted hunk ↗ jump to hunk
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c index 03079ff54889..8a08988ea9d1 100644 --- a/drivers/dma/idxd/sysfs.c +++ b/drivers/dma/idxd/sysfs.c@@ -1174,8 +1174,14 @@ static ssize_t wq_cdev_minor_show(struct device *dev, struct device_attribute *attr, char *buf) { struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev); + int minor = -1; - return sprintf(buf, "%d\n", wq->idxd_cdev.minor); + mutex_lock(&wq->wq_lock); + if (wq->idxd_cdev) + minor = wq->idxd_cdev->minor; + mutex_unlock(&wq->wq_lock); + + return sprintf(buf, "%d\n", minor);
As I mentioned, let's not emit a negative value here. ...not that
userspace should be using this awkward recreation of the existing core
'dev' attribute anyway.
if (minor == -1)
return -ENXIO;
return sprintf(buf, "%d\n", minor);